683 
fxus63 kmpx 151800 
afdmpx 


Area forecast discussion 
National Weather Service Twin Cities/Chanhassen Minnesota 
100 PM CDT Monday Mar 15 2010 


Update... 


Updated to include the 18z aviation discussion below. 


&& 


Discussion... 


Sundays high temperatures were very interesting as a surge of 
drier air from the NE...and 850 mb temperatures around 6c...allowed for surface 
temperatures to rise into the 50s and 60s. Minneapolis even broke a 
daytime high of 64. The main forecast concerns today will be the 
amount of cloud cover to the east vs. The western forecast area and how the surface 
temperatures will relate to these conditions with snow cover 
becoming less. 


Will likely lean toward the higher guidance temperatures (western wis) in 
the short term as cloud cover will likely be minimal. Elsewhere...will 
likely keep temperatures in check...but may adjust based on gembc which 
was the Superior model on sundays afternoon temperatures. 


As for precipitation chances...two weak upper level waves continue 
to move slowly east/southeast across the eastern Dakotas this morning. 
Although the rainfall has been locally heavy where these 
disturbances have nearly been stationary the past 24/48 hours...the 
general trend is to have the deepest moisture in the western forecast area 
today...with a slight increase in the east later tonight/Tuesday. 
My concerns deal with the movement of these waves further 
eastward into more cyclonic flow and become more sheared 
out. There may be enough to warrant 20/40% of -ra for eastern Minnesota 
starting later tonight/early Tuesday. Will see how the latest ec 
model indicates on moisture depth before increasing the 
percentages too much. Once this system moves south of the 
region...there should be enough subsidence to scourer out any 
residual moisture across the upper Midwest. 


After Thursday...the pattern change which we have been advertising 
the past few days will lead to uncertainties in precipitation 
chances over the weekend...and what type of precipitation at the 
early stages as the cold front moves through on late 
Thursday/Friday morning. Too many uncertainties to change current 
forecast with rain changing to snow by Friday night...with small 
chances of snow throughout the weekend. Temperatures will once 
again drop below normal and should last through the middle of next 
week. 


&& 






Aviation.../18z taf issuance/ 


High pressure stalled out over the Dakotas through Wednesday will 
keep conditions relatively constant before a significant pattern 
change starting Thursday. A weak disturbance noted in the WV 
imagery over the eastern Dakotas is moving east and weakening. It will 
provide a chance for rain across northern and central Minnesota 
tonight and into early Tuesday. Concern...may not see rain if the 
disturbance weakens too much. Can pretty much expect IFR 
conditions to continue into Tuesday morning at kaxn/krwf. Some 
very light rain may be noted after 03z at kaxn. Expect visibilities 
elsewhere to be similar to what we saw this morning...with 
ceilings in the VFR range until 08z and them becoming MVFR with a 
chance of IFR at kstc as we get closer to the areas that have had 
lower visibilities and ceilings for sometime now...closer to where we still 
have persistent snow cover on the ground. 




Kmsp... expect to see some scattering of clouds early this 
afternoon and may continue into evening per latest satellite 
imagery before lower clouds move in ahead of the weak disturbance. 
May even be sky clear for a few hours. Expect MVFR conditions to return 
around 08z or a tad after. 


Krnh/Keau...sky clear all afternoon into the evening hours with some low 
clouds after 01z and MVFR ceilings after 11z. 




&& 






Mpx watches/warnings/advisories... 
Minnesota...dense fog advisory until 1 PM CDT this afternoon for Blue Earth- 
Brown-Chippewa-Faribault-Freeborn-Lac Qui Parle-Martin- 
Nicollet-Redwood-Renville-Sibley-Steele-Stevens-swift- 
Waseca-Watonwan-Yellow Medicine. 


WI...none. 
&& 


$$ 


Trh/drl